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    <title>Document</title>
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    <script type="text/javascript">
        // 引入 events 模块
        var events = require('events');
        // 创建 eventEmitter 对象
        var eventEmitter = new events.EventEmitter();

        // 创建事件处理程序
        var connectHandler = function connected() {
            console.log('连接成功。');

            // 触发 data_received 事件 
            eventEmitter.emit('data_received');
        }

        // 绑定 connection 事件处理程序
        eventEmitter.on('connection', connectHandler);

        // 使用匿名函数绑定 data_received 事件
        eventEmitter.on('data_received', function() {
            console.log('数据接收成功。');
        });

        // 触发 connection 事件 
        eventEmitter.emit('connection');

        console.log("程序执行完毕。");
    </script>
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